1. Field of the Invention
This invention relates to a shield end processing structure in which a shield shell and a shield ring each having electrical conductivity are fixed to an end portion of a tubular shielding layer
2. Related Art
For example, in an electric car or a hybrid car, it is known that electromagnetic waves are generated from a large-current/high-voltage power cable (or wire) connected to a motor mounted on such a vehicle. Therefore, it has been important to provide electromagnetic shielding means which can prevent adverse effects of such electromagnetic waves and also can also prevent adverse effects of electromagnetic waves from the exterior. With respect to the electromagnetic shielding means, the following technique is disclosed in JP-A-2003-115223 Publication mentioned below.
In FIG. 3, reference numeral 1 denotes a shielding layer (braid) formed by interweaving electrically-conductive metal wire elements into a tubular shape. A plurality of wires 2 are passed through the interior of the shielding layer 1. The plurality of wires 2 are covered with the shielding layer 1. The plurality of wires 2 are passed, for example, through a hole 4 formed in a metal casing 3 of a motor. An end portion of the shielding layer 1 is connected and fixed to the metal casing 3 through a shield shell 5 having electrical conductivity. The fixing of the end portion of the shielding layer 1 to the shield shell 5 is effected by a fixing band 6 press-fastened to this end portion. The end portion of the shielding layer 1 is press-clamped to the shield shell 5 over an entire periphery thereof by the press-fastened fixing band 6.
Incidentally, with respect to the fixing of an end portion of a shielding layer to a shield shell, the following technique is also known. JP-A-11-262151 Publication mentioned below discloses a shield end processing structure in which a shield shell 11 and a shield ring 12 each having electrical conductivity are fixed to an end portion of a tubular shielding layer 13 by sliding movement of the shield ring 12 relative to the shield shell 11, as shown in FIG. 4. Outwardly-bent first rectangular piece portions 14 and inwardly-bent second rectangular piece portions 15 are formed at an end portion of the shield shell 11, and are alternately arranged in a circumferential direction.
The end portion of the shielding layer 13 is inserted between the outwardly-bent first rectangular piece portions 14 and the inwardly-bent second rectangular piece portions 15, and then the shield ring 12 is slid, thereby achieving the fixed condition. More specifically, when the shield ring 12 is slid, the outwardly-bent first rectangular piece portions 14 are bent inwardly, so that the end portion of the shielding layer 13 is firmly held between the first rectangular piece portions 14 and the second rectangular piece portions 15, thereby achieving the fixed condition.
Although the above-mentioned JP-A-11-262151 Publication is directed to the shield end processing structure for a shielded cable 16, such a shield end processing structure can be applied also to the structure described above with reference to FIG. 3.
The above conventional techniques have several problems. Namely, in the case of the structure of FIG. 3, the end portion of the shielding layer 1 is press-clamped to the shield shell 5 over the entire periphery thereof, and therefore there has been encountered a problem that unless the fixing band 6 is press-fastened to the end portion of the shielding layer 1 over the entire periphery thereof, the uniform press-clamped condition is not obtained. And besides, the entire-periphery press-fastening can not always be achieved with one press-fastening operation, and this leads to a possibility that the time and labor required for the end processing operation increase.
In the case of the structure of FIG. 4, the fixing of the end portion of the shielding layer 13 by the sliding movement of the shield ring 12 will not increase the time and labor for the end processing operation, and therefore this fixing method is satisfactory in this respect. However, in this structure in which there are provided the outwardly-bent first rectangular piece portions 14 and the inwardly-bent second rectangular piece portions 15, the shielding layer 13 can not be fixed uniformly over the entire periphery thereof (The shielding layer 13 is held between each second rectangular piece portion 15 and the shield ring 12 and also between side portions of any two adjacent first and second rectangular piece portions 14 and 15.). Also, when inserting the end portion of the shielding layer 13, this end portion is liable to be caught by edge portions of the first and second rectangular piece portions to become loose. Furthermore, when the outwardly-bent first rectangular piece portions 14 are bent inwardly, there is a possibility that the end portion of the shielding layer is cut by the first and second rectangular piece portions 14 and 15 as with scissors. Thus, the structure of FIG. 4 has the several problems mentioned above.